@rateme12/hook

The local client hook for rateme12: every tool call your agent makes against an MCP server becomes a task in the reputation ledger — without the payloads ever leaving your machine. Only a SHA-256 hash of the input and output, the tool name, the exact server version, latency, and the outcome are sent to rateme12 (docs/END_GOAL.md rows 4–5; docs/PRIVACY.md).

Two forms over one emit core:

1. Proxy binary (any MCP client, config-only)

Point your MCP client at rateme12-hook instead of the server; it spawns the real server and relays stdio, tapping tool calls in flight. Bytes flow host ↔ hook ↔ server locally; rateme12 sees only hashes.

{
  "mcpServers": {
    "some-server": {
      "command": "rateme12-hook",
      "args": ["--", "npx", "-y", "some-mcp-server"],
      "env": {
        "RATEME12_AGENT_KEY": "rm12_…",   // register at /install → returns a key
        "RATEME12_SERVER_ID": "<listing id from the directory>"
      }
    }
  }
}

Everything after -- is the downstream server command, run unchanged.

Config (env):

| Var | Required | Default | Meaning | |-----|----------|---------|---------| | RATEME12_AGENT_KEY | to emit | — | your agent's minted API key (rm12_…) | | RATEME12_SERVER_ID | to emit | — | the directory listing the server is | | RATEME12_API_BASE | no | https://api.rateme12.com | API origin | | RATEME12_MODEL | no | unknown | execution context (e.g. claude-opus-5) | | RATEME12_HARNESS | no | unknown | execution context (e.g. claude-code) | | RATEME12_VERSION | no | server's initialize version, else unknown | exact version override |

Without the key or server id the hook still runs — as a transparent pass-through, emitting nothing (a telemetry misconfig never breaks your agent).

2. Middleware (code that drives an MCP client)

Wrap your client's callTool; SDK-agnostic, no proxy process:

import { instrumentCallTool, resolveConfig } from "@rateme12/hook";

const { config } = resolveConfig(process.env);
const callTool = config
  ? instrumentCallTool(config, (args) => client.callTool(args), { version })
  : (args) => client.callTool(args);

The wrapped call is behaviourally identical — same result, same thrown errors; emission is fire-and-forget.

Running

Dev / from source (Bun): bun run src/cli.ts -- <server command>. The published rateme12-hook binary is the bundle produced by bun run bundle (dist/cli.js, Node ≥ 20).